COMPOSITE PIPES AND PROCESS FOR MANUFACTURING THE SAME

摘要

Improved composite pipes are proposed which comprise an outer pipe made of plastic and a thin lead layer on the inner wall of the outer pipe. The lead layer is formed by arranging a lead pipe in the outer pipe and expanding it by use of pressure medium into close contact with the inner wall of the outer pipe. The outer pipe may be circular or square or double-path. A process for producing the composite pipes is also proposed. 16